1. Field of the Invention
The present invention relates to a feeding unit and a media processing apparatus thereof. In particular, the present invention relates to a feeding unit and a media processing apparatus for media of varying thickness.
2. Description of Related Art
With the various recording media, users may feed the recording media of varying thicknesses into a media processing apparatus, for example a scanner, to scan the data recorded on the media. For example, paper of normal thickness may be fed to scan the data. Alternatively, the thicker media, such as credit cards, identification cards or another hard media, are scanned. For feed-in scanners, two corresponding rollers, which define a feeding port therebetween, are provided for normal force on the feeding media to achieve the better scanning quality. On the other hand, the normal force also refers to a feeding resistance, and the feeding motor of the scanner has to provide enough driving force to overcome the feeding resistance so as to feed the media in. The traditional structure of the feeding port is applied for paper of normal thickness. As a result, the thicker media can't be smoothly fed in because of the high feeding resistance caused by the interference of the thicker thickness and the two rollers. On the other hand, users sometimes feed the media of varying thickness in printers or fax machines; thus, the above-mentioned problem may occur in applications of printing or faxing.
A traditional method is providing high power throughput to drive larger motor to outputting more force to overcome the increased feeding resistance when the thicker media is fed. However, an extra voltage transformer or another high power supply is necessary for the above-mentioned method. Therefore, the cost and the volume of scanners, printers or fax machines are increased, and these apparatuses are not suitable for portable usage.
Taking scanners as an example, the portable scanners are powered by a power supply of 5V from a USB connector. When users need to scan the credit cards or identification cards by the USB-driven/USB-powered portable scanner, the force generated from the motor driven by the USB connector cannot overcome the increased feeding resistance. In other words, the traditional portable scanner which is powered by a USB connector cannot meet the requirement of scanning the thicker media.